The very very short tutorial about modules in Perl

There are two styles you can use for Perl modules. Both are useful under
different circumstances.

In the `exporting' style, the `module file' defines some functions
which you can load into your program and use as if you had defined
them yourself.

In the `object oriented' style, your module defines a `class' that
knows how to construct `objects' that perform actions on behalf of the
program when their methods are invoked.

You should visit the Module directory first. It
has an extremely simple module, an example program that uses it, and a
list of exercises. You should do all the exercises. When you are
done you will know how to write a module in the `module' style. The
examples are complete, but they are so simple that they will both fit
on the screen at the same time. Together they are eighteen lines long.

Then you should move to the Class directory,
which has an extremely simple object-oriented module, a sample
program, and a list of exercises. Do the exercsises. When you're
done you will know how to write a module in the `object oriented'
style. The example is a complete object-oriented program that creates
an object and calls a method on it. It is a little longer than the
other example. It is thirty-nine lines long. Fourteen of the lines
are blank.

There is also a third part, in the Inherit
directory. It shows how Perl does method inheritance in
object-oriented classes. You should do the exercises there last.